1. Field of the Invention
The present invention generally relates to an apparatus, a system, and a method for monitoring the conditions of a plurality of apparatuses which constitute a network.
2. Description of the Related Art
FIG. 1 illustrates an example of a monitoring system of the prior art. In FIG. 1, apparatuses 11 to 16 to be monitored are transmission apparatuses that constitute a network, for instance. The apparatuses 11 to 16 are connected to monitoring apparatuses 17 and 18 by a monitoring line 19, thereby forming a monitoring system.
There have been three conventional monitoring methods in which the monitoring apparatuses 17 and 18 monitor independently of each other the apparatuses 11 to 16 in a system of the above type. In a first monitoring method, the monitoring line is divided into two lines 19a and 19b, so that the monitoring apparatus 17 monitors and controls the apparatuses 11 to 13, and that the monitoring apparatus 18 monitors and controls the apparatuses 14 to 16, as shown in FIG. 2.
In a second monitoring method shown in FIG. 3, the monitoring line 19 is not divided, and the monitoring apparatus 17 monitors and controls the apparatuses 11 to 13 by polling them sequentially, while the monitoring apparatus 18 monitors and controls the apparatuses 14 to 16 by polling them sequentially.
In a third monitoring method shown in FIG. 4, the monitoring line 19 is not divided. The apparatuses 11 to 13 each have the address of the monitoring apparatus 17, and spontaneously send information to the address. In return, the monitoring apparatus 17 selectively controls the apparatuses 11 to 13. Likewise, the apparatuses 14 to 16 each have the address of the monitoring apparatus 18, and spontaneously send information to the address. In return, the monitoring apparatus 18 selectively controls the apparatuses 14 to 16.
The three conventional monitoring methods each have problems. In the first conventional monitoring method, the monitoring apparatus 17 cannot monitor the apparatuses 14 to 16, and the monitoring apparatus 18 cannot monitor the apparatuses 11 to 13, because the monitoring line is divided into the two separate monitoring lines 19a and 19b. This causes a problem that even if some trouble occurs in one of the monitoring apparatuses, the monitoring ranges cannot swiftly be changed.
As for the second conventional monitoring method, it takes the monitoring apparatuses a long time to recognize a trouble occurrence in one of the apparatuses 11 to 16, because the monitoring apparatuses 17 and 18 gather information by polling the apparatuses 11 to 16 one by one. Also, a larger number of apparatuses to be monitored applies a heavier load to the monitoring apparatuses, causing a problem that the monitoring apparatuses cannot adjust themselves to a larger system.
In the third conventional monitoring method, the apparatuses 11 to 16 to be monitored need to have the address of the monitoring apparatus 17 or 18 that is monitoring themselves, because the apparatuses 11 to 16 to be monitored each designate the address of the monitoring apparatus 17 or 18, and spontaneously send information to the monitoring apparatus of the designated address. In a case where more monitoring apparatuses are added, the apparatuses to be monitored have to send information to both the original monitoring apparatuses and the newly added monitoring apparatuses, resulting in more traffic. Also, since the monitoring range of each monitoring apparatus is fixed, changing the system configuration and distributing the monitoring apparatuses are difficult.
A general object of the present invention is to provide a monitoring apparatus, a monitoring system, and a monitoring method in which the above disadvantages are eliminated.
A more specific object of the present invention is to provide a monitoring apparatus, a monitoring system, and a monitoring method in which the monitoring ranges can swiftly be changed when trouble occurs in the monitoring apparatus, the time required for the monitoring apparatus to recognize the occurrence of trouble can be shortened, a larger system can be employed, and changing the system configuration and distributing the monitoring apparatuses can easily be carried out.
The above objects of the present invention are achieved by a monitoring system in which a monitoring apparatus monitors a plurality of apparatuses. In this monitoring system, the monitoring apparatus and the apparatuses to be monitored each have an address holding unit which holds the address of a group to which each apparatus belongs. A data frame to be transmitted between the monitoring apparatus and the apparatuses to be monitored has an identifier which specifies apparatus addressing communication or group broadcast. When the identifier specifies the group broadcast, a group address is put in the data frame.
In the above monitoring system, a plurality of monitoring apparatuses can be used for monitoring a large number of apparatuses which form a large-scale network and are divided into groups, and the group broadcast is carried out, thereby eliminating the need of polling. Thus, a load applied to each monitoring apparatus can be lighter than in the prior art, and a configuration change, such as increasing or reducing the number of monitoring apparatuses, can easily be made to the monitoring system.
The above objects of the present invention are also achieved by a monitoring apparatus which monitors a plurality of apparatuses. This monitoring apparatus comprises: a monitoring range holding unit which holds apparatus addresses of the plurality of apparatuses to be monitored as monitoring range data; a monitoring range comparing unit which judges whether a transmitter address in a transmitted data frame is included in the monitoring range data held in the monitoring range holding unit; and a condition display unit which displays a condition of a monitored apparatus based on contents of the transmitted data frame when the transmitter address is held in the managing range holding unit.
With the above monitoring apparatus, the system configuration can be flexibly changed depending on the form of the network constituted by the apparatuses to be monitored.
The above objects of the present invention are also achieved by a method of monitoring a monitoring system in which a monitoring apparatus monitors a plurality of apparatuses. This monitoring method comprising the steps of: storing a group address of a group to which each of the monitoring apparatus and the apparatuses to be monitored belongs; setting an identifier in a data frame to be transmitted between the monitoring apparatus and the apparatuses to be monitored, the identifier specifying communication between two apparatuses or group broadcast; and storing a group address in the data frame when the identifier specifies the group broadcast.
According to the above monitoring method, a plurality of monitoring apparatuses can be used for monitoring a large number of apparatuses which form a large-scale network and are divided into groups, and the group broadcast is carried out, thereby eliminating the need of polling. Thus, a load applied to each monitoring apparatus can be lighter than in the prior art, and a configuration change, such as increasing or reducing the number of monitoring apparatuses, can easily be made to the monitoring system.
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.